Enhanced Adsorption Properties of Noble Metal Modified MoS₂/WS₂ Heterojunctions

Abstract MoS 2 /WS 2 in‐plane heterojunction is constructed using density functional theory (DFT), and its adsorption properties for different gas molecules (CO, CO 2 , NO 2 , H 2 S, SO 2 , and SO 3 ) are analyzed. Results indicate that the heterojunction exhibits excellent selection toward S‐series gas molecules (H 2 S, SO 2 , and SO 3 ), particularly SO 3 . The adsorption energy is determined to be −3.67 eV. Then, the adsorption properties of the heterojunction are further improved by noble metal (Ag, Au, and Pt) modification. Noble metal atoms alter the surface potential energy of the heterojunction, resulting in stronger adsorption activity. For instance, the binding energies of noble metals in the Ag‐MoS 2 /WS 2 , Au‐MoS 2 /WS 2 , and Pt‐MoS 2 /WS 2 systems are −1.03, −1.04, and −2.76 eV, respectively. Additionally, there has been a significant alteration in their bandgaps. Notably, the bandgap of Pt‐MoS 2 /WS 2 has decreased to 1.42 eV (24.16%), which is the most pronounced change. Then, the charge density difference and density of states of noble metal‐modified MoS 2 /WS 2 heterojunction adsorbed SO 3 are analyzed. The results demonstrate that the adsorption capacity of a noble metal‐modified system for SO 3 is enhanced. Finally, raising the temperature can accelerate gas molecule desorption from the system. Combining all calculation results, Ag‐MoS 2 /WS 2 in‐plane heterojunction can be used as a candidate gas‐sensitive material for detecting SO 3 at room temperature (300 K). The Pt‐MoS 2 /WS 2 in‐plane heterojunction is demonstrated to possess effective adsorbent properties for trapping SO 3 gas molecules at room temperature. This provides a new idea and theoretical basis for gas sensor development.